This invention relates generally to color television cameras, and more particularly to such cameras having two or more solid-state imaging devices.
Solid-state imaging devices, such as CCD imagers, are recently used as image-pickup devices of television cameras. One problem involved in the application of such solid-state imaging devices to television cameras is that the resolution of an image obtained from the output signal of such solid-state imaging device is not as high as conventional pickup tubes. In order to better the resolution, therefore, various techniques have hitherto been taken, one of which is a pixel-offsetting method.
The pixel-offsetting method is actualized using two or more solid-state imaging devices having a number of pixels (picture elements) arranged horizontally and vertically. For instance, in a known three-chip CCD color TV camera, a CCD chip for green light (G) is positioned such that its horizontal position with respect to an incident image of a subject to be imaged is shifted by half pitch of pixels in the horizontal direction from two other CCD chips for red light (R) and blue light (B) so that signals from the red and blue pixels are shifted by half a period which corresponds to the pitch of the pixels with respect to signals from green pixels thereby reducing aliasing noise and improving resolution. On the other hand, in a known two-chip CCD color TV camera, a CCD chip for green light (G) is positioned such that its horizontal position with respect to an incident image of a subject to be imaged is shifted by half pitch of pixels in horizontal direction from the other CCD chip for red light (R) and blue light (B) where a color separation filter for transmitting green light is applied to the CCD chip for green light, and another color separation filter for causing the other CCD chip for red and blue light to produce an output picture signal including red signal components and blue signal components which are line-sequentially outputted, is applied to the other CCD chip.
However, even though such spatially pixel-offsetting method is used, since the fundamental frequency of color signals obtained from such known two or more chips of solid-state imaging devices is the same as that in a conventional TV camera involving no pixel-offsetting, it has been difficult to obtain high-quality color pictures with such TV cameras using two or more solid-state imaging devices.